Imaginary Exercise

You don't even have to move to experience some of the effects of physical activity.

It's pretty much what you'd expect: heart rate, blood flow, breathing rate, and blood pressure go up when you're running compared to resting. The walking values tend to be somewhere between resting and running. So what's the catch? The subjects in this study were sitting in a reclining chair the whole time – the only difference is that they were watching a video that someone took while resting, walking and running. So the changes in heart rate and breathing were purely anticipatory responses generated by the brain.

This phenomenon is actually pretty well known and studied. In fact, previous studies have produced much higher changes in physiological parameters by asking subjects to imagine themselves running or participating in a race. Other studies have produced somewhat higher results using "third-person" video – i.e. a video showing someone else running. This study, published in the journal Frontiers in Autonomic Neuroscience by researchers at the University of Western Sydney, tried using "first-person" video filmed from the perspective of the runner, to see if it would engage the brain more effectively. The answer turned out to be "no": the pulse increase of ~2 beats/minute is very modest compared to previous studies.

Still, it's a pretty cool phenomenon, and shows that how your body responds to exercise depends in part on how you perceive and interpret it. We're not just machines; state of mind matters.